The present invention relates to a method for producing 5-phenoxycarbonylbenzotriazole.
5-Phenoxycarbonylbenzotriazole is a compound of formula (I): 
which is a useful material for the production of photosensitive materials. There was disclosed in Japanese Patent Kokai No. 269,156/99 a method of reacting 1H-benzotriazole-5-carboxylic acid of formula (II): 
with triphenyl phosphite.
The method, however, has a problem in that phosphite ester is formed as a by-product in substantially the same amount as that of the desired 5-phenoxycarbonyl-benzotriazole and the treatment thereof was tedious.
According to the process of the present invention, 5-phenoxycarbonylbenzotriazole of formula (I) can be produced in a good yield from 1H-benzotriazole-5-carboxylic acid (II) and diphenyl carbonate of formula (III): 
thereby the amount of a by-product accompanying the reaction is not only reduced but also the treatment thereof is facilitated.
The present invention provides a method for producing 5-phenoxycarbonylbenzotriazole, comprising reacting 1H-benzotriazole-5-carboxylic acid with diphenyl carbonate.
The amount of diphenyl carbonate used in the method of the present invention is usually at least one mole, preferably, 5 moles or less, and more preferably, 3 moles or less per one mole of 1H-benzotriazole-5-carboxylic acid.
The reaction of the present invention is usually conducted in the presence of a base or a metal oxide. Examples of the base that may be used in the present invention include an organic and inorganic bases. Examples of the organic base include diisopropylethylamine (pKa=11) N,Nxe2x80x2-dimethylaminopyridine (pKa=9.71), 1,4-diazabicyclo[2.2.2]octane (pKa=8.7), N-methylmorpholine (pKa=7.41), imidazole (pKa=6.99), N-methylimidazole (pKa=7.1), pyridine (pKa=5.42), etc. xe2x80x9cpKaxe2x80x9d values cited in the parentheses above mean an acid dissociation constant of a conjugated acid of each compound. Preferred organic bases are organic bases of which conjugated acid has an acid dissociation constant pKa of 7.2 or more in view of the desired product yield.
Examples of the inorganic base include an alkali metal carbonate such as sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate or the like; an alkali metal hydroxide such as lithium hydroxide, sodium hydroxide, or potassium hydroxide; and an alkaline earth metal hydroxide such as magnesium hydroxide, calcium hydroxide, or cesium hydroxide. The metal oxides usable in the present invention include, for example, magnesium oxide, barium oxide, zinc oxide, lead monoxide, or calcium oxide.
A catalytic amount of the base or metal oxide may be used in the reaction, and typically the base or metal oxide is used in an amount of 2 moles or less, preferably, 0.5 mole or less; or usually, at least 0.001 mole, preferably, at least 0.01 mole per mole of 1H-benzotriazole-5-carboxylic acid.
For example, an organic base such as pyridine or N-methylimidazole, which can be present in a liquid form, can be used in an amount of 20 parts by mass, preferably, 7 parts or less by mass, and more preferably, 2 parts or less by mass per one part by mass of 1H-benzotriazole-5-carboxylic acid.
The reaction according to the present invention is usually carried out in a solvent. The base, which is liquid under the reaction conditions, may be used as a solvent. Examples of the solvents that may be used in this reaction include, for example, an aprotic polar solvent such as N,N-dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, or N,N-dimethylacetamide usually in an amount of 20 parts by mass, preferably, 7 parts or less by mass, and more preferably, 2 parts or less by mass per one part by mass of 1H-benzotriazole-5-carboxylic acid.
The reaction of the present invention is usually conducted by mixing 1H-benzotriazole-5-carboxylic acid with diphenyl carbonate in a solvent, and preferably the base or metal oxide may be used in such a way that the base or metal oxide is added to the mixture of 1H-benzotriazole-5-carboxylic acid, diphenyl carbonate and the solvent. The base, which is liquid under the reaction conditions, can be mixed with 1H-benzotriazole-5-carboxylic acid and diphenyl carbonate without using a solvent.
The reaction of the present invention is usually conducted at 60xc2x0 C. or higher, preferably, 70xc2x0 C. or higher; and usually, 160xc2x0 C. or lower, preferably, 140xc2x0 C. or lower.
In the reaction, carbon dioxide and phenol are formed as by-products, however, the former can be easily evacuated out of the reaction system.
To obtain 5-phenoxycarbonylbenzotriazole from the resulting reaction mixture, for example, the compound can be obtained by evaporating a reaction solvent out of the mixture, extracting with a suitable solvent, and/or collecting after crystallization with a solvent. The crystallization is usually conducted, for example, by cooling the reaction mixture, or an evaporated mixture thereof dissolved in a suitable solvent, precipitating the desired product under cooling, and collecting the precipitated product by filtration. Typically the crystallization is conducted by using an insufficient solvent, which is usually added to the reaction mixture or an evaporated mixture thereof.
Examples of the insufficient solvent include, for example, an alcohol such as methanol, ethanol, or isopropanol; an aliphatic hydrocarbon such as hexane, or heptane; water; and an aromatic hydrocarbon such as toluene or the like. Preferred are the alcohol and water in view of the filtrability, and more preferred is a mixture of water and the alcohol.